Electrolytes in modern electrochemical appliances like lithium ion batteries, electrochromic devices and capacitors are made from various organic solvents containing conductive lithium salts like lithium tetrafluoroborate, lithium hexafluorophosphate, lithium bisoxalatoborate, lithium triflate, lithium bistriflylamide, etc. Such organic solvents (like alkyl carbonates, acetonitrile, N-methyl-2-pyrrolidone, γ-butyrolactone and many others) have a serious disadvantage. They can indeed ignite and, in the worst cases, cause an overheated appliance to explode and start a fire.
Attempts have been made to circumvent this disadvantage of organic solvents by using ionic liquids (IL) as solvents, as described for example in U.S. Pat. Nos. 6,365,301 and 6,365,068, U.S. Patent Application Nos 2008/0266642 and 2009/0045373, and PCT publication No. WO 2009/013046.
Existing ionic liquids however do not solve all the problems associated with the manufacturing of electrochemical appliances, especially high power lithium or lithium ion batteries. In batteries, several electrode materials are used, so solvents or electrolytes for use with these materials should exhibit high thermal, electrochemical and chemical stabilities.
Tetraalkylammonium salts, including cyclic analogs like piperidinium, morpholinium, pyrrolidinium and azepanium, have the widest electrochemical window.1 The most used IL for electronic applications are those containing bis(trifluoromethanesulfonyl)amide anions (TFSA or TFSI), which have oxidation stability close to that of BF−4 and PF−62 and exhibit the widest liquid range.
Electrochemical intercalation of lithium into graphite anodes in 1-ethyl-3-methylimidazolium (EMI) based ionic liquids has aroused interest because these ionic liquids have low viscosities and high conductivities. However, these ionic liquids have narrow electrochemical windows (ca 4.2 V). Imidazolium cations are prone to being reduced at the electrode/electrolyte interface when the carbon electrode is polarized to 0.7 V vs. Li/Li+. The strong decomposition reaction of the cations prevents the formation of LiC6 compounds. The addition of a solvent may however stabilize and protect the interface between a carbon negative electrode and the ionic liquid phase against an undesirable irreversible reaction with the ionic liquid component. N. Koura, and coworkers demonstrated the formation LiC6 compound in LiCl-EMICl—AlCl3 ionic electrolyte containing SOCl2.3 Satisfactory results were obtained for various carbonaceous materials. Holzapfel et al. presented the lithium intercalation into an artificial graphite in 1 M solution of LiPF6 in 1-ethyl-3-methyl imidazolium bis(trifluoromethylsulfonyl)imide (EMI-TFSI) containing 5 wt % of vinylene carbonate (VC) as an additive.4 
However, despite many attempts, no pure ionic liquid providing reversible charging-discharging of a graphitized negative electrode at ambient temperature without any additives has been reported yet. The practical application of the imidazolium derivatives into lithium ion batteries is difficult. Lithium ion batteries using these ionic liquids suffer from relatively small voltage. Graphite material, which is used as a low potential anode material in lithium ion batteries, can cause reduction of unsaturated IL and consequent decomposition, especially of imidazolium and pyridinium based IL. In some cases, the intercalation of cations of IL has caused the exfoliation of graphite layer.
Recently there have been some reports on ionic liquid electrolytes based on bis(fluorosulfonyl)imide (FSI) for rechargeable Li batteries. In particular, FSI-based electrolytes containing Li-ion exhibited practical ionic conductivity, and a natural graphite/Li cell with FSI-based electrolytes containing Li bis(trifluoromethanesulfonyl)imide (LiTFSI) showed cycle performance without any solvent, using 1-ethyl-3-methylimidazolium (EMIm)-FSI and EMIm-TFSI5 and using IL based on bis(fluorosulfonyl)imide (FSI)6 as anion and 1-ethyl-3-methylimidazolium (EMI) and N-methyl-N-propylpyrrolidinium (Py13) as cations. It has further been observed that IL with TFSI anion cannot be used alone with graphite electrodes, because only very low capacities could be reached. The use of stabilizing agents like lithium bis(fluorosulfonyl)amide (FSI) in electrolyte and the preparation of IL containing fluorosulfonyl trifluoromethanesulfonylamide (FTFSI) was proposed7, but these solutions are economically not viable due to the high cost of LiFSI salt and complicated synthesis method.
Choline-like compounds, possessing 2-hydroxyethyl group, are able to form deep eutectic mixtures, but are not suitable for use in electrochemical appliances with high operating voltage because of the presence of labile acidic hydroxyl groups. The methylation of hydroxyl groups in choline like compound may however improve their stability.
Improvement of stability of various oligoethylene glycols was achieved by the protection of terminal hydroxyl group by various siloxy groups, such as trimethylsilyl group.8 The preparation of silylated choline compounds has also been disclosed.9 
JP 2010-095473A discloses ionic compounds containing trialkylsilyl moieties and their use as antistatic agents for low surface energy polymers (PTFE). The prepared antistatic agents were mostly solid at room temperature.
There is thus a need for novel ionic compounds or ionic liquids for use in electrolytes and electrochemical cells.